Hollywood, FL—Sunitinib and pazopanib have long battled for supremacy in treating advanced renal-cell carcinoma (RCC). According to findings presented at the National Comprehensive Cancer Network 20th Annual Conference, the newer drug, pazopanib, may have some benefit in total cost of care; survival outcomes were the same between drugs.

An independent study comparing costs and health outcomes in initial therapy for RCC showed sunitinib had a mean total cost of care $12,000 higher than pazopanib, according to lead author Patrick Racsa, MS, a Research Scientist at Comprehensive Health Insights of Humana Inc, Louisville, KY.

“Survival and treatment characteristics were similar for both index medications, but medication and total healthcare costs trended higher with sunitinib treatment, despite higher pre-index total costs in the pazopanib group,” stated Laura E. Happe, PharmD, MPH, a Strategic Consultant at Humana Inc, Louisville. “Nonadherence with sunitinib was associated with significantly higher total healthcare costs, which may indicate unfavorable tolerability with sunitinib treatment.” This hypothesis is based on tolerability shown in clinical trials, but was not proved in this study, Dr Happe emphasized.

The authors indicated that sunitinib and pazopanib, 2 tyrosine kinase inhibitors (TKIs), are both approved, first-line options for patients with advanced RCC; clinical evidence and national guidelines do not differ between these therapies. Two comparative cost studies based on data from COMPARZ (Pazopanib Versus Sunitinib in the Treatment of Locally Advanced and/or Metastatic Renal Cell Carcinoma) and PISCES (Patient Preference Study of Pazopanib Versus Sunitinib in Advanced or Metastatic Kidney Cancer) showed pazopanib was less costly and more cost-effective than sunitinib, but these findings were based solely on clinical trial data.

The purpose of this study was to compare treatment characteristics (treatment interruption, adherence, duration, and discontinuation), survival, and costs for new users of sunitinib and pazopanib for advanced RCC in an observational setting, Dr Happe explained.

First Real-World Comparison

“To our knowledge this is the first head-to-head comparison of these 2 TKIs in a real-world setting,” Dr Happe observed. “We are looking at our Humana global universe of millions of lives. This study was not funded by either manufacturer…which makes it a very unique analysis.”

The study was an observational retrospective cohort with ≤12 months of follow-up among patients receiving sunitinib (n = 241) and pazopanib (n = 112) for ≥6 months. The authors defined treatment interruptions as therapy gaps of >30 days. Adherence was quantified using proportion of days covered, which was calculated as days prescribed divided by total days of follow-up.

“We saw no difference in overall survival, which supports the COMPARZ trial,” Dr Happe said. “About 55% of patients remained alive after 1 year. Treatment interruptions and adherence were also the same. From everything we can garner from claims, in terms of efficacy, the drugs were the same.”

Treatment Cost Comparison

The authors also examined mean total healthcare costs, broken down by component medical and pharmacy costs, and stratified by adherent status.

“Total costs were the same,” Dr Happe reported. “Sunitinib was higher numerically ($76,624 vs $64,432), but this was a nonsignificant trend (adjusted P = .07). The only component approaching statistical significance (P = .05) was pharmacy index medication, which reflects the price of the drug. Sunitinib was $5000 more expensive ($26,984 vs $21,404)…. All other costs were the same.” Although it was not found to be statistically significant, pazopanib was numerically less expensive in total medical and pharmacy costs.

One of the study’s most interesting findings was the statistically significant difference in costs between drugs within the nonadherent subgroup, she added. These were $82,730 for sunitinib, and $65,040 for pazopanib (P = .01). One suggestion for this difference was a possible increase in side effects on sunitinib leading to greater cost of care as patients sought treatment for toxicities. “We don’t know what’s driving this difference in cost,” acknowledged Dr Happe. “Clinical trials have shown some differences in tolerability, meaning sunitinib may be less tolerable than pazopanib.”

With the similarities in efficacy between sunitinib and pazopanib by National Comprehensive Cancer Network or clinical trials, the higher costs of sunitinib will be an important consideration in choice of treatment, the authors concluded.

“We validated no clinical difference between these drugs,” Dr Happe concluded. “And from a medical standpoint, you are only looking at the price of the drug. If your health plan gets a good discount on these drugs, you might consider these drugs interchangeable.”